Join the show as we talk with retired Army strategist and West Point professor Matt Cavanaugh . Matt is the only living kidney donor to complete RacingThePlanet's 4 Deserts Grand Slam—an ultramarathon series considered one of the toughest endurance challenges on earth. After earning two Bronze Stars in Iraq, Matt hit a personal low. In an act of radical generosity, he donated a kidney to a stranger—sparking a donation chain that saved seven more lives. Just months after surgery, he raced across four continents in a single year, turning personal scars into strength. His new book, Best Scar Wins, out December 2, 2025, features a foreword by ultrarunning legend Dean Karnazes and combines lessons from combat, extreme endurance, and intentional recovery to explore what it really takes to turn pain into purpose.